This invention relates to storm windows and in particular to those storm windows and third glazings which can be added in an aftermarket context to improve the insulating capability of the building in which they are used.
Previous third glazings have had the disadvantage that they must be installed as original equipment on the building or replace the entire window and frame, on the one hand, or the glazing must be removed separately from the frame on the other.
An example of the first instance is Potter, U.S. Pat. No. 3,992,815, issued Nov. 23, 1976, wherein a complete window unit is described, including a permanent conventional sliding window and an extruded frame member for holding the screen or storm window, which can be locked into place. Replacing an existing window with this system would clearly be more expensive than adding a third glazing to an existing window system.
An example of the second instance is Casamayor, U.S. Pat. No. 4,184,297, issued Jan. 22, 1980, which shows hinged perimeter and jointer strips holding insulating panels on larger windows. Here, if the storm window is to be removed the framing strip must be unsnapped and opened, and the glazing only removed from the frame. The glazing must then assumably be carried and stored unframed, in which case breakage or other damage is a real possibility.
This invention relates to solutions to the disadvantages and problems raised by the inventions described above.